Articles containing non-visible identifying marks formed from carbon nanomaterials and methods utilizing the same

Abstract

Identifying marks are often used for authentication and tracking purposes with various types of articles, but the marks themselves can sometimes be subject to replication or removal by an outside entity, such as a person or group having malicious intent. This can make it easier for an outside entity to produce a counterfeit article or to sell a stolen article. Carbon nanotubes and other carbon nanomaterials can be used to form identifying marks that are not visible to the naked eye, thereby making the marks more difficult for an outside entity to tamper with. Various articles can include an identifying mark that is localized and not visible to the naked eye, the identifying mark being electrically conductive and containing a carbon nanomaterial. By electrically interrogating the article, such as through spatially measuring eddy currents about the article, the marks can be located and authenticated.

What is claimed is the following: 
     
       1. An article comprising:
 a matrix; and 
 a subsurface identifying mark that is configured for indirect electrical interrogation, is localized within the matrix and is not visible to a naked eye, the subsurface identifying mark being electrically conductive and comprising a carbon nanomaterial. 
 
     
     
       2. The article of  claim 1 , wherein the matrix comprises a non-conductive matrix material, and the identifying mark does not increase a bulk conductivity of the non-conductive matrix material. 
     
     
       3. The article of  claim 1 , wherein the carbon nanomaterial comprises carbon nanotubes, graphene, any functionalized variant thereof, or any combination thereof. 
     
     
       4. The article of  claim 3 , wherein the carbon nanomaterial comprises at least carbon nanotubes, and the carbon nanotubes have a registered distribution of chiralities. 
     
     
       5. The article of  claim 3 , wherein the article comprises more than one subsurface identifying mark, each subsurface identifying mark being spatially separated in the article. 
     
     
       6. The article of  claim 5 , wherein one or more of the subsurface identifying marks comprise a different carbon nanomaterial or combination thereof than do the remaining subsurface identifying marks. 
     
     
       7. The article of  claim 5 , wherein one or more of the subsurface identifying marks comprise a different amount of carbon nanomaterial or combination thereof per unit area than do the remaining subsurface identifying marks. 
     
     
       8. The article of  claim 1 , wherein the article is an electrical device comprising an electronic component. 
     
     
       9. The article of  claim 8 , wherein the subsurface identifying mark is in electrical communication with the electronic component. 
     
     
       10. An article comprising:
 more than one identifying mark comprising a carbon nanomaterial, each identifying mark being localized and spatially separated in the article, not visible to a naked eye, and electrically conductive;
 wherein at least a portion of the identifying marks are in resonant communication with one another. 
 
 
     
     
       11. A method comprising:
 providing an article in need of tracking, the article comprising a matrix and a subsurface identifying mark incorporated within the article, the subsurface identifying mark being localized within the matrix, electrically conductive, and not visible to a naked eye, and comprising a carbon nanomaterial; 
 operationally deploying the article; and 
 after operationally deploying the article, electrically interrogating the article to locate and assay the subsurface identifying mark. 
 
     
     
       12. The method of  claim 11 , wherein electrically interrogating the article comprises scanning the article with an eddy current probe. 
     
     
       13. The method of  claim 11 , wherein the matrix comprises a non-conductive matrix material, and the identifying mark does not increase a bulk conductivity of the non-conductive matrix material. 
     
     
       14. The method of  claim 11 , wherein the carbon nanomaterial comprises carbon nanotubes, graphene, any functionalized variant thereof, or any combination thereof. 
     
     
       15. The method of  claim 14 , wherein the carbon nanomaterial comprises at least carbon nanotubes, and the carbon nanotubes have a registered distribution of chiralities. 
     
     
       16. The method of  claim 14 , wherein the article comprises more than one subsurface identifying mark, each subsurface identifying mark being spatially separated in the article. 
     
     
       17. The method of  claim 16 , wherein at least a portion of the subsurface identifying marks are in resonant communication with one another. 
     
     
       18. The method of  claim 16 , wherein one or more of the subsurface identifying marks comprise a different carbon nanomaterial or combination thereof than do the remaining subsurface identifying marks. 
     
     
       19. The method of  claim 16 , wherein one or more of the subsurface identifying marks comprise a different amount of carbon nanomaterial or combination thereof per unit area than do the remaining subsurface identifying marks. 
     
     
       20. A method comprising:
 providing an article in need of tracking, the article comprising an identifying mark, the identifying mark being localized, electrically conductive, and not visible to a naked eye, and comprising a carbon nanomaterial;
 wherein the carbon nanomaterial comprises at least carbon nanotubes having a registered distribution of chiralities; 
 
 operationally deploying the article; 
 after operationally deploying the article, electrically interrogating the article to locate and assay the identifying mark; 
 obtaining a fluorescence spectrum or a Raman spectrum of the identifying mark; 
 determining a distribution of carbon nanotube chiralities in the identifying mark from the fluorescence spectrum or the Raman spectrum; 
 comparing the distribution of carbon nanotube chiralities to the registered distribution of chiralities; and 
 authenticating the identifying mark based on its electrical properties and the distribution of carbon nanotube chiralities.